1. Field of the Invention
This invention relates to an apparatus which graphically demonstrates the angle and magnitude of displacement of a projectile in relationship to the bore axis of a gun at the precise instant the projectile exits from the muzzle. The present invention also provides means for monitoring the structural integrity of the projectile in the proximity of the muzzle.
2. Description of the Prior Art
Various means have been used in the past to measure the parameters that relate to improvement of a gun's accuracy. Among these parameters, it has been established that excessive yaw and pitch at the muzzle exit can affect the free flight trajectory of the projectile and may in many instances be indicative of gun tube wear and other projectile-gun tube interface problems. Thus, knowledge of the initial orientation (yaw and pitch) characteristics of the projectile can result in refinement of projectile design to provide increased accuracy. With the recent increased emphasis in high performance gun-projectile systems, which are costly to manufacture, knowledge of the structural integrity of the projectile at launch becomes increasingly important.
Normally because of the tight tolerances between a projectile and its gun tube, the angles of yaw and pitch are quite small. In the past, these small angles of yaw and pitch have been difficult to detect by photographic methods. X-ray photographs are not suitable for this purpose because they are not sufficiently well-defined to see a small angle. Use in the past of regular photography has been unsatisfactory in many instances, because the projectile is usually obscured by smoke and blast effects. Use of lasers or a multiple interferometer system to observe the projectile is also not practical because of smoke and blast obscurant effect. Another problem with use of the aforementioned devices to measure projectile yaw and pitch angle at the muzzle is that they are relatively expensive and require a fixed mounting and realignment whenever the gun firing angle is changed.